Heat treatment apparatus

ABSTRACT

Apparatus for the heat treatment of annular metal components such as rings for rolling element bearings is disclosed. The apparatus is designed to be automatic and to take up less space in a factory production line. This is achieved by providing a tempering furnace and an annealing furnace each with at least one substantially vertical conduit through which a stack of the components can be transported in the axial direction of the stack. The conduits are arranged to be slightly larger than the diameter of the component being treated and there are provided means for creating a flow of heat exchange fluid through each furnace respectively, the flow of heat exchange fluid being in a direction opposite the direction of movement of the components. This allows each component to go through exactly the same temperature changes for exactly the same length of time as each other which is an advantage over previous systems in which the rings have been treated in irregular orientations where the temperature gradients within a furnace result in each component being raised to a slightly different temperature for different lengths of time resulting in a lack of uniformity in the eventual hardness of different finished components.

United States Patet n 1 Claesson et al.

[451 Apr. 17, 1973 HEAT TREATMENT APPARATUS [75] Inventors: Georg Claesson, Gladwyne, Pa;

Renato Battini, Turin, Italy [73] Assignee: RlV-SKF Officine di Villar Perosa S.p.A., Turin, Italy [22] Filed: NOV. 22, 1971 [21] Appl. No.: 200,940

52 us. Cl. ..266/4 R, 266/9 [51 1 Int. Cl. ..C21d 9/40 [58] Field of Search ..266/4 R, 4 B, 4 s, 266/9 [56] References Cited UNITED STATES PATENTS 3,143,628 8/1964 7 Golden ..266/4 R Primary Examiner--Gerald A. Dost Attorney-Richard C. Sughrue et a1.

[ 1 ABSTRACT Apparatus for the heat treatment of annular metal components such as rings for rolling element bearings is disclosed. The apparatus is designed to be automatic and to take up less space in a factory production line. This is achieved by providing a tempering furnace and an annealing furnace each with at least one substantially vertical conduit through which a stack of the components can be transported in the axial direction of the stack. The conduits are arranged to be slightly larger than the diameter of the component .being treated and there are provided means for creating a flow of heat exchange fluid through each furnace respectively, the flow of heat exchange fluid being in a direction opposite the direction of movement of the components. This allows each component to go through exactly the same temperature changes for exactly the same length of time as each other which is an advantage over previous systems in which the rings have been treated in irregular orientations where the temperature gradients within a furnace result in each component being raised to a slightly different temperature for different lengths of time resulting in a lack of uniformity in the eventual hardness of different finished components.

20 Claims, 13 Drawing Figures PATENTEDAPR 1 H915 5. 727. 896

SHEET 2 [1F 7 PATENTEUAPRIYIQB I 3.727, 896

SHEET 3 UF 7 T FigS HEAT TREATMENT APPARATUS BACKGROUND OF THE INVENTION The present invention relates to equipment for heat treatment of annular metal components such as rings which are to form parts of rolling element bearings.

According to the known art, heat treatment of rings for rolling element bearings takes place in plant comprising: an austenite (tempering) furnace operating at a r temperature varying from 850 C to 870 C, within which the rings, which have diameters of between 30 mm. and 80mm. remain for approximately 20 to 30 minutes; quenching apparatus such as a bath of oil or other fluid into which the rings leaving the austenite furnace are discharged in a random orientation; cooling apparatus having running cold water at a temperature in the region of 14 C to 16 C; washing apparatus for washing the components in hot water and detergent; drying apparatus operating to dry the components by means of blown air; and finally an annealing furnace operating at a temperature of between 150 C and 170 C within which the components remain for about an hour.

. Such known heat treating equipment as described above is quite cumbersome, taking up an overall length of about 20 meters, and this is a disadvantage in factories with limited space where it is necessary,

whenever possible, to reduce to a minimum the space taken up by machinery in the production sectors of the factory.

One arrangement which is used in known types of heat treating apparatus is to have the heating furnaces for austeniting (tempering) and annealing in the form of tunnels having considerable horizontal length and to have the oil quenching apparatus in the form of a long tank filled with oil into which the components leaving the heating furnace fall by gravity to be conveyed along the length of the tank by a mechanical transporter which gradually travels the length of the tank and is raised above the edge of the tank at the end of its travel.

Known heat treating equipment is, in general, not satisfactory for the high production rates required today since it is not adequately adapted for handling the quantity of components which are produced in other parts of the factory, and which arrive in a more or less constant stream along conveying channels leading to the furnace. To satisfy present day technical production requirements it is advantageous if the heating furnace for tempering can be inserted into a line having apparatus for effecting various other heat treatment processes, and including the apparatus for producing the rings so that the complete production line may be of limited length. I

It is also, of course, preferable for the heat treating equipment to be of low cost so that there may be as many heat treatment units as there are production lines for the different types of rings most required on the market. Naturally all these requirements should be met by apparatus capable of producing a finished product the quality of which is not lower, and is preferably better, than that of rings treated in previously known apparatus.

OBJECTS OF THE INVENTION One object of the present invention is to provide apparatus for heat treatment of the rings or rolling element bearings, which apparatus does not suffer from the disadvantages of known types of heating treating apparatus and which enables the needs of present technical production practice to be satisfied. The present invention also seeks to provide heat treatment apparatus which can provide a product of improved quality.

Another object of the present invention is to provide heat treatment apparatus with which any variation of the hardness index of the components being treated is sufficiently restricted to lie within close tolerances even if the time in which the components remain in the annealingfumace is shorter than that which is required for satisfactory production utilizing known heat treating equipment.

SUMMARY OF THE INVENTION According, therefore, to the present invention, there is provided apparatus for heat treatment of annular metal components such as'rings for rolling element bearings, of the type comprising a tempering furnace, means for quenching the components at a high speed for tempering them as they leave the furnace, means for washing and for drying the components, an annealing furnace, and means for transporting the components through the apparatus, characterized in that the tempering and annealing furnaces are each provided with at least one substantially vertical conduit through which a stack of the components can be transported, the conduit having an internal diameterv greater than the diameter of the components to be treated, there being provided means for creating a flow of heat exchange fluid through the conduit in a direction opposite the direction of advancement of the components.

Further advantages and features of the present invention will become more apparent from a consideration of the following description with reference to the accompanying drawings which is given by way of example only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of the embodiment of the invention as a whole;

FIG. 2 is a diagrammatic perspective view of part of the embodiment of FIG. 1, showing the internal part of the tempering furnace;

FIG. 3 is a vertical section of another part of the embodiment of FIG. 1, showing the annealing furnace;

FIG. 4 is a vertical section of the annealing furnace taken on the line IV IV of FIG. 3;

FIG. 5 is a horizontal section of the annealing furnace taken on the line V V of FIG. 3;

FIG. 6 is a horizontal sectional view of a further part of the embodiment of FIG. 1 showing the oil spraying device for quenching;

FIG. 7 is a vertical sectional view of the oil spraying device for quenching taken on the line VII VII of FIG. 6;

FIGS. 8, 9, l0, l1 and Rare diagrammatic illustrations of a device for loading the rings into the heating furnace, showing the device in various operating positions; and

FIG. 13 is a qualitative diagram of the hardness of the components after treatment, as a function of the time they remain in the annealing furnace at various operating temperatures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2 the heat treatment apparatus illustrated comprises a heating furnace l for tempering the components. The furnace comprises a chamber 2 defined by lateral walls 7 and 8, within the chamber 2 there is a second chamber 3 which is defined by lateral walls 4 and 5. The second chamber 3 has an opening 6 at the bottom, and is spaced from the internal walls 7 and 8 of the chamber 2 so as to form an intervening space 9 within the chamber 2 and surrounding the intemal chamber 3. The internal walls 7 and 8 are provided with some form of heating devices such as, for example, electrical heating elements indicated by the reference numeral 10. The walls 4 and of the internal chamber 3 are provided, near the bottom opening 6, with apertures 11 and 12. The intervening space 9 is filled with a non-oxidizing gas such as nitrogen, which is supplied through a passageway 13 connected by a pipe 14 to a gas source or gas container 15. In the top of the chamber 3 there is fitted a fan 16 which is driven by an electric motor 17 by means of a shaft 18. The fan 16 causes the non-oxidizing gas to circulate around the closed path defined between the chamber 2 and chamber 3, as illustrated by the arrows in FIG. 1.

The components which are to undergo the heat treatment which in this embodiment are rings for rolling element bearings, are shown by the reference numeral 19; these are fed through the heating furnace l for tempering in a plurality of stacks 20 (see FIG. 2) which are aligned with one another in a row. The stacks 20 of components pass through the bottom wall 21 of the furnace 1 through an aperture 22 which is coaxial with the center line of the internal chamber 3. The annular components are fed to the bottom of the stacks 20 one at a time, by means which will be described below, under the bottom wall 21 of the furnace 1 from a hopper 23 for each stack 20, along respective horizontal lines on a surface 24.

The components 19 are removed from the furnace l at the upper part of the furnace through a conduit 25 extending through the lateral wall 4 of the internal chamber 3 and the wall 8 of the outer chamber 2. The components are moved by the action of a pusher device 26 which reciprocates within a guide conduit 27 extending through the wall 5 of the internal chamber 3 and aligned with the conduit 25. It will be appreciated that there are as many conduits 25, 2 7 as there are stacks 20 of components within the chamber 3.

From the arrangement shown in FIGS. 1 and 2 it will be seen that the circulation of the non-oxidizing gas, nitrogen, within the chamber 3 is in a direction opposed to the direction of advancement of the components 19 which, in the embodiment shown, is upwards from the bottom as shown by the arrow F. In the space 9, on the other hand, the direction of movement of the gas is the same as the direction of advancement of the components 19 within the furnace.

At the outlet of the tempering furnace the components 19 are pushed along a surface diagrammatically illustrated in FIG. 1 and denoted by the reference numeral 28, which leads to the final phases of the treatment of the components, which will be described below.

With particular reference to FIGS. 8 to 12, the arrangement for inserting the components 19 into the furnace 1 will be described. This arrangement is mounted on the previously mentioned horizontal surface 24 which extends below the bottom wall 21 of the furnace, and comprises the hopper 23 into which are stacked the components 19 as they are received from the part of the factory where the immediately preceding treatment is effected. The hopper 23 is spaced from the plane 24 by a distance equal to at .least the thickness of one component 19; the area below the hopper 23 is indicated by the reference numeral 29 and within this area there operates a wedge-shaped pusher 30 which is moved reciprocally by a rod 31 of an hydraulic actuator 32, only part of which is shown in the drawings. The wedge-shaped pusher 30 supports the components 19 present in the hopper 23 when in the position shown in FIG. 8, that is when inserted into the area 29. The pusher 30 is connected by means of a rod 33 to a finger device 34' which operates in the area 35 between the surface 24 and the vertical conduit 36 which leads to the aperture 22 in the bottom wall 21 of the furnace 1. The finger device 34 acts in conjunction with the wedge-shaped pusher device 30 in the sense that when the wedge-shaped device 30 is moved away from the space 29 (see FIG. 10) the finger 34 is moved into position below the conduit 36 by the rod 33, and supports the stack 20 of components 19 which extends into the furnace l.

The device for moving the components 19 vertically up into the furnace 1 comprises a fork-shaped pusher 37 which is movable perpendicularly to the plane 24 through an opening 38. The fork 37 is positioned to move the stack 20 axially in order to move the components 19 into the furnace 1. The fork 37 is also arranged to cooperate with the finger 34 and is so positioned that the finger 34 can extend between the prongs 39 of the fork 37 as will be described below. The fork 37 is mounted for vertical reciprocating movement on an hydraulic actuator 40 having an operating rod 41 and so positioned that the fork 37 is raised when the operating rod 41 is extended. The furnace loading device operates as follows:

With reference to FIGS. 8 to 12, when the wedgeshaped pusher device 30 controlled by the hydraulic actuator 32 draws back (to the left of the drawings), a

' component 19 slides down from the hopper 23 onto the surface 24; at the same time the stack 20 is being supported by the prongs 39 of the fork 37 and the finger 34 is being inserted between the prongs 39 since it is moved in unison with the pusher 30. In this position the fork 37 can be lowered by retracting the actuator 41 without lowering the stack 20 since it is now supported by the finger 34. Theactuator 32 can now be extended to move the pusher 30 towards the right and to push a new part 19 into line with the conduit 36 for subsequent insertion into the furnace; at the same time the wedge-shaped device 30 during its advance, moves so as to support the components 19 present in the loading hopper 23 and the finger 34 withdraws so that the column 20 is again supported on the fork 37. Extension of the actuator 40 follows and the cycle then recommences.

Referring now to FIG. 1 and to FIGS. 6 and 7, it will be seen that the components 19 emerging from the furnace 1 are quenched (for tempering) be an oil jet indicated at 42. This oil jet is produced by a spray arrangement generally indicated 43. The oil after having passed over the components 19 is collected in a reservoir 44 from the bottom of which it is recycled by a pump 45 along a conduit 46 which carries it back to the spraying device 43. Along the flow path of the oil, in the conduit 46 there is a heat exchanger 47 for cooling the oil which is heated during the quenching of the components 19. Over the spraying 49 for collecting the oil vapor formed on quenching.

With particular reference now to FIGS. 6 and 7 the above mentioned spray device 43 will be described in greater detail. The spray 43 comprises a cylindrical casing 50 defining an internal chamber 51 which is open at the bottom, and closed at the top by a wall 52. Inside the chamber 51 there is arranged a second cylindrical casing 53 closed at one end and supported from the lateral walls of the casing 50 by screws 54. Between the casing 50 and casing 53 there is a space 55 within which there is an annular element 56 also held in position by the screws 54 which support the casing 53. The annular element 56 defines two intermediate annular concentric spaces 55a and 55b having substantially the same diameters respectively as the internal diameter and external diameter of the components 19. Oil is fed to the inside of the chamber 51 via an inlet connection '57 and is distributed from the chamber 51 into two concentric annular jets 42a and 42b which impinge on the part 19 at the inside and outside curved surfaces thereof. A further conduit 58 open at 59 and extending between the two casings 50 and 53 serves for allowing the escape of oil vapors formed in the spraying zone, upon quenching, to balance the pressure within the spraying zone with respect to the surroundings.

After quenching for tempering the components 19 are moved further along the surface 28 where they are washed with running water fed to sprays 60 via a conduit 61 and collected by a reservoir 62 which has a discharge outlet 63. After the washing treatment the components 19 are washed again, this time with hot water at about 70 C in an arrangement comprising a sprayer 64, to which the hot water arrives through a conduit 65, and a collection reservoir 66, which is furnished with a reheating device comprising a plurality of electric heating resistances 67. The hot water is drawn off from the bottom of the reservoir 66 by a circulation pump 68 and from there it is conveyed to the sprayer 64. Before entering the annealing furnace 69 the components 19 undergo further treatment by compressed air sprayed by a nozzle 70 which is fed with compressed air through a conduit 71.

Referring again to FIG. 1, and also to FIGS. 3, 4 and 5, one embodiment of the annealing furnace 69 will be described. The components 19 pass into the annealing furnace 69 through an aperture 72 in an external wall 75 of the furnace. The aperture 72 is arranged to be at the same horizontal level as the surface 28 along which the components 19 are pushed one at a time by the pusher 26 after leaving the tempering furnace 1. The

furnace 69 comprises an internal chamber 74 defined by lateral walls 73 and 75, by a top wall 76, and by a bottom wall 77. In the chamber 74 the components 19 are arranged in stacks 78 to be annealed. The stacks 78 are located laterally by corrugated elements 79, 80 the corrugations of which define partially open conduits for the stacks 78. Discharge of the components 19 from the furnace is effected from the bottom 69 thereof through an opening 81 which is closable by a flexible element 82. The components 19 are pushed laterally by a pusher 83 which is operated by the operating rod 84 of an hydraulic actuator 85 and are discharged along a slide 86 into a collection container 87. The support surface for the stack 78 is formed by the bottom wall 77 of the furnace 69, which is provided with apertures 88 through which hot air is blown inside the chamber 74 of the furnace 69.

The hot air passes through the chamber 74 from bottom to top in a direction opposite that in which the components 19 are moving through the same chamber of the furnace 69 (that is, from top to bottom) and is circulated by a fan 89 which takes it from the top of the chamber 74 where there are a plurality of electrical heating resistances 90 for heating the air, through a conduit 91, and delivers it to an inlet manifold 92. In the manifold 92, which is located below the bottom wall 77 of the furnace there is a butterfly valve 93 for evenly dividing the air flow. The butterfly valve is controlled by a handwheel 94 on a shaft 95. The fan 89 is driven by an electric motor (not shown) and is supported by a bracket 97 projecting from the supporting frame 98 of the furnace. The other parts of the apparatus, described above, are also supported by suitable frames which are all generally indicated by the reference numeral 98.

With the heat treatment apparatus described above it is possible to form production lines having limited longitudinal extent since, as may be seen, the paths of the components being heated in the furnaces (that is the tempering furnace of the annealing furnace), run vertically, and the quenching and washing operations are effected not by immersion of the components in vats but by spraying the components with appropriate fluids as they are advanced.

Moreover, in the heat treatment apparatus described above there are provided parallel rows of components which are simultaneously subjected to the same heat treatment; this is particularly suitable for simultaneously treating components from different parts of the production system, which may be of slightly different shape or of different sizes; of course, there must be suitable differences in the shape and size of the handling members to cater for these differences in the components handles, but this 'can be quite readily achieved.

The diagram shown in FIG. 13 illustrates that components treated in apparatus such as that described above have improved quality over those made by known apparatus, especially with respect to hardness. This result is due in particular to the restricted space occupied by the components within the furnaces and to the effective circulation of the warning air through which the temperature differences between one point and another within the furnace are kept to a minimum; the temperature at which the components are accurately and continuously maintained while they are in the furnaces is arranged to be just that temperature at which the hardness which it is desired to obtain is best produced; with the traditional processes on the other hand, where the components have been fed into the furnaces in a disoriented array, in order to ensure that all the components are adequately raised to the hardening temperature for long enough, it is necessary for the rings (components) on the outside of the array to be subjected to a treatment which is longer than necessary, and therefore the varous components will vary in hardness.

The greater precision at which the temperature of each component can be maintained makes it possible to have annealing temperatures higher than those which can be used with known furnaces thereby saving a considerable amount of time.

In fact, as will be seen from FIG. 13, the annealing furnace 69 of this embodiment of the invention allows the safe use of an annealing temperature (curve C) higher than that (curve A) employed in known furnaces where the hardness interval (S) is obtained only after a time duration (R) much greater than the duration (R2) which is required for annealing at the higher temperature (C). It is clear that variation of the duration of time (R) for which the components are held at the annealing temperature has much less consequence than the same variation in the duration (R2), so that deliberate variations in the components can be readily achieved.

it will be appreciated that the apparatus illustrated and described by way of example may be changed by diverse and numerous variations of construction without nevertheless departing from the scope of this invention as described and claimed hereinafter.

What is claimed is:

1. ln apparatus for the heat treatment of annular metal components comprising in combination: I

a tempering furnace within which said components are raised to a high temperature,

means for quenching said components at a high speed to temper them as they leave said tempering furnace,

means for washing and drying said components as they leave said quenching means,

an annealing furnace, and

means for transporting said components through said apparatus:

the improvement wherein said tempering furnace and said annealing furnace are both provided with at least one respective substantially vertical conduit, said means for transporting said components through said apparatus being operative to transport at least one stack of said components through respective said conduits in the axial direction of each said stack, each said conduit having an internal diameter greater than the diameter of said components thereby defining a space around said components stacked within each said furnace, and

means for creating a flow of heat exchange fluid through said conduit at least in said space between said conduit and said stack of components in the direction opposite the direction of advance of said stack of components through said conduit.

2. The apparatus of claim 1 wherein said tempering furnace includes means defining an internal chamber open at one end thereof, said chamber being shaped to receive a plurality of said stacks of annular components in a row within said chamber,

means for supporting each stack from below,

means for introducing said components into said furnace,

means defining an external chamber surrounding said internal chamber and defining, in combination with said means defining said internal chamber a passageway for the circulation of said heat exchange fluid,

means for heating said heat exchange fluid, said heating means being mounted on said means defining said external chamber, and

said means for creating a flow of heat exchange fluid being operative to circulate said heat exchange fluid in said passageway and said space so that said heat exchange fluid travels in said passageway in the opposite direction from its direction of travel in said space.

3. The apparatus of claim 2 wherein there are provided means defining an opening in said means defining said external chamber,

means for feeding a supply of said heat exchange fluid through said opening into said external chamber, said external chamber communicating with said internal chamber at least by means of said open end of said internal chamber.

4. The apparatus of claim 1 wherein said means for creating a flow of heat exchange fluid comprises a fan, said fan being driven by an electric motor.

5. The apparatus of claim 1 wherein said heat exchange fluid is a non-oxidizing gas.

6. The apparatus of claim 5 wherein said non-oxidizing gas is nitrogen.

7. The apparatus of claim 2 wherein said means for introducing said components into said tempering furnace are operative to insert said components at the lower part of said furnace and to extract the components from the upper part of said furnace, said open end of said internal chamber being the bottom end thereof.

8. The apparatus of claim 7 wherein said means for transporting said stack of components through said furnace is operative to transport said components in the axial direction of said stack, said transport means comprising a first pusher device operating along the axial direction of said stack of components,

a second pusher device operating transverse said axial direction of said components alternately with said first pusher device so as to transfer said components one by one to said stack.

9. The apparatus of claim 8, wherein said means for introducing said components into said tempering furnace comprise a horizontal surface extending underneath said furnace and along which said components can slide,

a hopper for containing a stack of said components before they are fed to said furnace, the bottom component of said stack in said hopper resting on said horizontal surface, the bottom of said hopper being spaced from said horizontal surface by a distance at least equal to the thickness of each of horizontal surface, the end of said hollow conduitbeing spaced from said horizontal surface by a distance-at least equal to the thickness of each of said components, said first pusher device reciprocating in line with the axis of said hollow conduit and transversely to the plane of said horizontal surface and operating to engage the component at the bottom of said stack extending through said hollow conduit, said first and said second pusher devices operating alternately. 10. The apparatus of claim 9 wherein said second pusher includes a wedge shaped device mounted for reciprocating movement towards and away from said tempering furnace in said space between the bottom of said hopper and said horizontal surface, said wedge shaped device operating to support said stack of components in said hopper as it advances towards said tempering furnace and at the same time pushing the bottom component of said stack in said hopper along said horizontal surface.

11. The apparatus of claim 10 wherein there is a rod connecting said wedge shaped device of said second pusher to a finger device located below the end of said hollow conduit extending down from the bottom of said tempering furnace, said finger device operating to support said stack of components in said furnace and cooperating with said first pusher which operates to raise said stack of components into said furnace, the end of said first pusher being in the form of a fork having two prongs so that when first pusher is in said raised position said prongs of said fork extend on either side of said finger device.

12. The apparatus of claim 1 wherein there are provided means for extracting said components one at a time from the top of the or each stack in said tempering furnace, said extracting means comprising at least one transverse conduit extending through the side walls of said tempering furnace adjacent the top of the or each said stack of components, each said transverse conduit being at least as wide as the diameter of said components and at least as high as the thickness of said 13. The apparatus of claim 1 wherein said means for 6 quenching said components as they leave said tempering furnace comprise, in combination:

a second horizontal surface along which said components are pushed by said third pusher device toward said annealing furnace,

spraying means for spraying quenching fluid over said components,

a reservoir for collecting said quenching fluid after it has been sprayed over said components,

means for recirculating said quenching fluid to said spraying means, and

means in the recirculation path of said quenching fluid for reconditioning said quenching fluid before it returns to said spraying means.

14. The apparatus of claim 13 wherein said spraying means comprise,

a first cylindrical casing open at the bottom thereof, means mounting said first cylindrical casing over said second horizontal surface in the path of said components,

a second cylindrical casing also open at the bottom, means mounting said second cylindrical casing coaxially within said first cylindrical casing,

an annular element mounted between said first cylindrical casing and said second cylindrical casing, said annular element being shaped to define, with said first and second cylindrical casings, two concentric annular cavities which are both open at the bottom, the outer said annular cavity having a diameter substantially equal to the outer diameter of said annular components and the inner said annular cavity having a diameter substantially equal to the inner diameter of said annular components, and

means for supplying quenching fluid to said concentric annular cavities.

15. The apparatus of claim 13 wherein there are provided means for washing said quenching fluid from said components after they have been quenched and before they reach said annealing furnace, said washing means comprising,

spraying means located over said second horizontal surface between said quenching means and said annealing furnace,

a reservoir for collecting said washing water after it has been sprayed over said components,

recirculating means for returning said washing water from said reservoir to said spraying means, and

means for reconditioning said washing water before it is returned to said spraying means.

16. The apparatus of claim 1 wherein said annealing furnace comprises,

means defining an elongate substantially vertical furnace chamber,

means for guiding at least one substantially vertical stack of components through said annealing furnace chamber, said at least one substantially vertical stack of components being supported by a bottom surface of said annealing furnace chamber, said means for guiding said at least one stack of components through said chamber maintaining said at least one stack of components spaced from the walls of said annealing furnace chamber,

means defining an aperture in one wall of said annealing furnace chamber adjacent the top of said at least one stack of components therein,

means for introducing said components one by one into said annealing furnace chamber onto the top of said at least one stack,

means defining an opening in one side wall of said annealing furnace chamber adjacent the bottom of said at least one stack of components, means for discharging said components from said annealing furnace chamber one by one from the bottom of said at least one stack of components,

means defining a plurality of apertures in said bottom surface of said annealing furnace chamber,

means defining a manifold chamber under said bottom surface of said annealing furnace chamber, said manifold chamber communicating with said annealing furnace chamber through said plurality of apertures in said bottom surface of said annealing furnace chamber,

means for creating a flow of air into said annealing furnace chamber through said manifold chamber and via said plurality of apertures, said flow of air being in a direction opposite the direction of travel of said stack of components in said annealing furnace chamber, and

means for heating said air flowing within said annealing furnace chamber.

17. The apparatus of claim 16 wherein said means for creating a flow of air into said annealing furnace chamber comprise,

a fan,

an electric motor driving said fan,

a conduit connecting the top of said annealing furnace chamber with said manifold chamber, and means for dividing the flow of air within said manifold chamber.

18. The apparatus of claim 17 wherein said means for heating said air flowing in said annealing furnace chamber comprise heat radiating elements located in said upper part of said furnace chamber in a region thereof above said stack of components therein, said heat radiating elements being located in the path of the air circulating through said annealing furnace chamber.

19. The apparatus of claim 16 wherein said at least one opening in said side wall of said annealing furnace chamber adjacent the top of said at least one stack of components is aligned with said second horizontal surface over which said components move during said quenching and washing operations, said third pusher which operates to discharge said components from said tempering furnace and to transfer said components along said second horizontal surface operating to push said components one by one into said annealing furnace onto the top of said at least one stack of components therein.

20. The apparatus of claim 19 wherein said annealing furnace is provided with at least one fourth pusher device mounted for reciprocating motion through an opening in said annealing furnace chamber wall opposite said discharge opening adjacent the bottom of said stack of components in said annealing furnace, said at least A pusher device operating to push the bottom component of said stack out of said furnace, the remainder of said stack being restrained laterally by said means for guiding said stack through said annealing furnace chamber.

UNITED STATES PATENT OFFICE CERTIFI CATE OF CORRECTION Patent No 3,727 8% Dated April 17,1973

' lmi'zentojr-(sf Georg Claessor et a1 1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I i I II I IE1" Thej fleading The claim to priority was omitted. Shoulql read:

December-29, 1970, 7 Italy ..71d325-A/70 Signed and Sealed this 27th day of November 1973.

(SEAL). Attest:

EDWARD M.ELETC ER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patentsl FORM FO-1OS0 (10-69) USCOMM'DC 603764 69 U.S. GOVERNMENT PRINTING OFFICE: I969 0-366-334, 

1. In apparatus for the heat treatment of annular metal components comprising in combination: a tempering furnace within which said components are raised to a high temperature, means for quenching said components at a high speed to temper them as they leave said tempering furnace, means for washing and drying said components as they leave said quenching means, an annealing furnace, and means for transporting said components through said apparatus: the improvement wherein said tempering furnace and said annealing furnace are both provided with at least one respective substantially vertical conduit, said means for transporting said components through said apparatus being operative to transport at least one stack of said components through respective said conduits in the axial direction of each said stack, each said conduit having an internal diameter greater than the diameter of said components thereby defining a space around said components stacked within each said furnace, and means for creating a flow of heat exchange fluid through said conduit at least in sAid space between said conduit and said stack of components in the direction opposite the direction of advance of said stack of components through said conduit.
 2. The apparatus of claim 1 wherein said tempering furnace includes means defining an internal chamber open at one end thereof, said chamber being shaped to receive a plurality of said stacks of annular components in a row within said chamber, means for supporting each stack from below, means for introducing said components into said furnace, means defining an external chamber surrounding said internal chamber and defining, in combination with said means defining said internal chamber a passageway for the circulation of said heat exchange fluid, means for heating said heat exchange fluid, said heating means being mounted on said means defining said external chamber, and said means for creating a flow of heat exchange fluid being operative to circulate said heat exchange fluid in said passageway and said space so that said heat exchange fluid travels in said passageway in the opposite direction from its direction of travel in said space.
 3. The apparatus of claim 2 wherein there are provided means defining an opening in said means defining said external chamber, means for feeding a supply of said heat exchange fluid through said opening into said external chamber, said external chamber communicating with said internal chamber at least by means of said open end of said internal chamber.
 4. The apparatus of claim 1 wherein said means for creating a flow of heat exchange fluid comprises a fan, said fan being driven by an electric motor.
 5. The apparatus of claim 1 wherein said heat exchange fluid is a non-oxidizing gas.
 6. The apparatus of claim 5 wherein said non-oxidizing gas is nitrogen.
 7. The apparatus of claim 2 wherein said means for introducing said components into said tempering furnace are operative to insert said components at the lower part of said furnace and to extract the components from the upper part of said furnace, said open end of said internal chamber being the bottom end thereof.
 8. The apparatus of claim 7 wherein said means for transporting said stack of components through said furnace is operative to transport said components in the axial direction of said stack, said transport means comprising a first pusher device operating along the axial direction of said stack of components, a second pusher device operating transverse said axial direction of said components alternately with said first pusher device so as to transfer said components one by one to said stack.
 9. The apparatus of claim 8, wherein said means for introducing said components into said tempering furnace comprise a horizontal surface extending underneath said furnace and along which said components can slide, a hopper for containing a stack of said components before they are fed to said furnace, the bottom component of said stack in said hopper resting on said horizontal surface, the bottom of said hopper being spaced from said horizontal surface by a distance at least equal to the thickness of each of said components, said second pusher device operating transversely on said stack in said hopper to push said component at the bottom of said stack along said horizontal surface by a distance at least equal to the diameter of said component, means defining at least one opening in the bottom of said means defining said external chamber of said tempering furnace, a hollow conduit extending downwardly from said at least one opening towards said horizontal surface, said stack of components in said furnace extending through said conduit and being supported on said horizontal surface, the end of said hollow conduit being spaced from said horizontal surface by a distance at least equal to the thickness of each of said components, said first pusher device reciprocating in line with the axis of said hollow conduit and transversely to the plane of said horizontal surface anD operating to engage the component at the bottom of said stack extending through said hollow conduit, said first and said second pusher devices operating alternately.
 10. The apparatus of claim 9 wherein said second pusher includes a wedge shaped device mounted for reciprocating movement towards and away from said tempering furnace in said space between the bottom of said hopper and said horizontal surface, said wedge shaped device operating to support said stack of components in said hopper as it advances towards said tempering furnace and at the same time pushing the bottom component of said stack in said hopper along said horizontal surface.
 11. The apparatus of claim 10 wherein there is a rod connecting said wedge shaped device of said second pusher to a finger device located below the end of said hollow conduit extending down from the bottom of said tempering furnace, said finger device operating to support said stack of components in said furnace and cooperating with said first pusher which operates to raise said stack of components into said furnace, the end of said first pusher being in the form of a fork having two prongs so that when first pusher is in said raised position said prongs of said fork extend on either side of said finger device.
 12. The apparatus of claim 1 wherein there are provided means for extracting said components one at a time from the top of the or each stack in said tempering furnace, said extracting means comprising at least one transverse conduit extending through the side walls of said tempering furnace adjacent the top of the or each said stack of components, each said transverse conduit being at least as wide as the diameter of said components and at least as high as the thickness of said components, a third pusher device in the or each said conduit in one of said walls of said furnace, said pusher device being mounted for reciprocating movement and acting laterally on the top component of the stack or the stack associated therewith to push said component into the corresponding conduit in said other side wall of said tempering furnace to discharge said components one by one as they reach the top of a stack.
 13. The apparatus of claim 1 wherein said means for quenching said components as they leave said tempering furnace comprise, in combination: a second horizontal surface along which said components are pushed by said third pusher device toward said annealing furnace, spraying means for spraying quenching fluid over said components, a reservoir for collecting said quenching fluid after it has been sprayed over said components, means for recirculating said quenching fluid to said spraying means, and means in the recirculation path of said quenching fluid for reconditioning said quenching fluid before it returns to said spraying means.
 14. The apparatus of claim 13 wherein said spraying means comprise, a first cylindrical casing open at the bottom thereof, means mounting said first cylindrical casing over said second horizontal surface in the path of said components, a second cylindrical casing also open at the bottom, means mounting said second cylindrical casing coaxially within said first cylindrical casing, an annular element mounted between said first cylindrical casing and said second cylindrical casing, said annular element being shaped to define, with said first and second cylindrical casings, two concentric annular cavities which are both open at the bottom, the outer said annular cavity having a diameter substantially equal to the outer diameter of said annular components and the inner said annular cavity having a diameter substantially equal to the inner diameter of said annular components, and means for supplying quenching fluid to said concentric annular cavities.
 15. The apparatus of claim 13 wherein there are provided means for washing said quenching fluid from said components after they have been quenched and before they reach said annealing furnace, said washing means comprising, spraying means located over said second horizontal surface between said quenching means and said annealing furnace, a reservoir for collecting said washing water after it has been sprayed over said components, recirculating means for returning said washing water from said reservoir to said spraying means, and means for reconditioning said washing water before it is returned to said spraying means.
 16. The apparatus of claim 1 wherein said annealing furnace comprises, means defining an elongate substantially vertical furnace chamber, means for guiding at least one substantially vertical stack of components through said annealing furnace chamber, said at least one substantially vertical stack of components being supported by a bottom surface of said annealing furnace chamber, said means for guiding said at least one stack of components through said chamber maintaining said at least one stack of components spaced from the walls of said annealing furnace chamber, means defining an aperture in one wall of said annealing furnace chamber adjacent the top of said at least one stack of components therein, means for introducing said components one by one into said annealing furnace chamber onto the top of said at least one stack, means defining an opening in one side wall of said annealing furnace chamber adjacent the bottom of said at least one stack of components, means for discharging said components from said annealing furnace chamber one by one from the bottom of said at least one stack of components, means defining a plurality of apertures in said bottom surface of said annealing furnace chamber, means defining a manifold chamber under said bottom surface of said annealing furnace chamber, said manifold chamber communicating with said annealing furnace chamber through said plurality of apertures in said bottom surface of said annealing furnace chamber, means for creating a flow of air into said annealing furnace chamber through said manifold chamber and via said plurality of apertures, said flow of air being in a direction opposite the direction of travel of said stack of components in said annealing furnace chamber, and means for heating said air flowing within said annealing furnace chamber.
 17. The apparatus of claim 16 wherein said means for creating a flow of air into said annealing furnace chamber comprise, a fan, an electric motor driving said fan, a conduit connecting the top of said annealing furnace chamber with said manifold chamber, and means for dividing the flow of air within said manifold chamber.
 18. The apparatus of claim 17 wherein said means for heating said air flowing in said annealing furnace chamber comprise heat radiating elements located in said upper part of said furnace chamber in a region thereof above said stack of components therein, said heat radiating elements being located in the path of the air circulating through said annealing furnace chamber.
 19. The apparatus of claim 16 wherein said at least one opening in said side wall of said annealing furnace chamber adjacent the top of said at least one stack of components is aligned with said second horizontal surface over which said components move during said quenching and washing operations, said third pusher which operates to discharge said components from said tempering furnace and to transfer said components along said second horizontal surface operating to push said components one by one into said annealing furnace onto the top of said at least one stack of components therein.
 20. The apparatus of claim 19 wherein said annealing furnace is provided with at least one fourth pusher device mounted for reciprocating motion through an opening in said annealing furnace chamber wall opposite said discharge opening adjacent the bottom of said stack of components in said annealing furnace, said at least 1/4 pusher device operating to push the bottom component of said stack out Of said furnace, the remainder of said stack being restrained laterally by said means for guiding said stack through said annealing furnace chamber. 